High voltage gas type circuit interrupters in tandem with a center break disconnecting switch



Oct-.3, 1967 1.. v. CHABALA ET L 3,

HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS IN TANDEM WITH A CENTER BREAKDISCONNECTING SWITCH l0 Sheets-Sheet 1 v Filed Dec. 20. 1965 Oct 3, 1967L. v. CHABALA ET AL 3,

HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS IN TANDEM WITH A CENTER BREAKDISCONNECTING SWITCH Filed Dec. 20, 1965 10 Sheets-Sheet 2 3,345,473 EMWITH L. V. CHABALA ET AL Oct. 3, 1967 HIGH VOLTAGE GAS TYPE CIRCUITINTERRUPTERS IN TAND A CENTER BREAK DISCONNECTING SWITCH l0 Sheets-Sheet5 Filed Dec. 20, 1965 |||Lll [\tlllll Illf Oct. 3, 1957 v, CHABALA ET AL3,345,473

HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS IN TANDEM WITH A CENTER BREAKDISCONNECTING SWITCH l0 Sheets-Sheet 4 Filed Dec. 20. 1965 3,345,473 EMWITH Oct. 3, i967 L.,V. CHABALA ET AL TYPE CIRCUIT INTERRUPTERS IN TAN ACENTER BREAK DISCONNECTING SWITCH HIGH VOLTAGE GAS Filed Dec. '20, 196510 Sheets-Sheet 5 Oct. 3, 1967 C B L ET AL 3,345,473

HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS IN TANDEM WITH A CENTER BREAKDISCONNECTING SWITCH Filed Dec. 20, 1965 10 Sheets-Sheet 6 Oct. 3, 1967v. CHABALA ET AL 3,345,473

HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS IN TANDEM WITH Filed Dec. 20.1965 A CENTER BREAK DISCONNECTING SWITCH l0 Sheets-Sheet '7 Oct. 3, 1967L. v. CHABALA ET AL 35 HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS INTANDEM WITH v A CENTER BREAK DISCONNECTING- SWITCH Filed D80. 20, 196510 Sheets-Sheet 8 Oct. 3, 1967 v gHABALA ET AL 3,345,473

HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS IN TANDEM WITH A CENTER BREAKDISCONNECTING SWITCH 3.0 Sheets-Sheet 9 Filed Dec. 20. 1965 Oct. 3, 1967L. v. CHABALA ET AL 3,

HIGH VOLTAGE GAS TYPE CIRCUIT INTERRUPTERS IN TANDEM WITH A CENTER BREAKDISCONNECTING SWITCH Filed Dec. 20, 1965 10 Sheets-Sheet 10 UnitedStates Patent ABSTRACT OF THE DHSCLOSURE A single mechanism common totwo serially connected separable contact circuit interrupters opens andcloses the contacts simultaneously in conjunction with the opening andclosing of a series connected center break disconnecting switch.

This invention relates, generally, to circuit interrupters for use withcircuits operating at 500 kv., 60 cycle alternating current in which theload current flow normally does not exceed 2,000 amperes and in whichthe fault current may be of the order of 44,000 amperes symmetrical. Itcan be employed on circuits operating at higher or lower voltages, atdifferent frequencies, and for different current ranges.

It constitutes an improvement over the inventions disclosed in Gussow etal. U.S. Patent 3,030,481 issued Apr. 17, 1962, Mikos et al. U.S. Patent3,163,736, issued Dec. 29, 1964, Mikos U.S. Patent 3,194,928, issuedJuly 13, 1965, and Bernatt U.S. Patent 3,244,826, issued Apr. 5, 1966.

Among the objects of this invention are: To provide for synchronizingthe operation of series connected high voltage circuit interrupters suchthat the contacts thereof can be opened substantially simultaneously orwithin less than one quarter of a half cycle of 60 cycle alternatingcurrent; to employ for this purpose a walking beam to the distal ends ofwhich contact operating members are mechanically connected; to bias thewalking beam to open the contacts and to provide a latch cooperatingwith the walking beam to hold the contacts closed and against thisbiasing action; to pry open the contacts by further operation of thelatch if the biasing means is incapable of initiating opening of thecontacts; to provide a rotatable mechanism cam for tripping the latch,rotating the walking beam to reclose the contacts of the circuitinterrupters and for winding up the spring that biases them to the openpositions; to arrange for the mechanism cam to trip the latch atdifferent operating positions of the cam; to provide for over travel ofthe mechanism cam after the contacts are latched in their closedpositions; to provide each circuit interrupter with at least one pair oftranslatory separable main contacts in parallel circuit relation with apair of translatory separable auxiliary contacts, each pair of contactshaving a translatory operating member individual thereto con- .nectedrespectively to the distal ends of first and second walking beams; tooperatively interconnect the first and second walking beams and torotate them by the spring,

first to substantially simultaneously open the pairs of separable maincontacts and next by substantially simultaneously opening the pairs ofseparable auxiliary contacts; to operatively interconnect the first andsecond walking beams by a tie spring and by mutally engageable abutmentmeans; to provide another latch for preventing opening of the pairs ofseparable auxiliary contacts and to trip this latch when the firstwalking beam is rotated to a predetermined position; to rotatably mountthe walking beams on a shaft and to secure the mechanism cam forrotation with this shaft with the spring being wound by torque appliedto the shaft at one end and transmitted by the mechanism cam to thefirst walking beam; to secure the mechanism cam to the shaft adjacentthe end where the torque is applied whereby the torque is required to betransmitted only through a relatively short length of the shaft; torotatably mount the second walking beam on the first walking beam,thereby confining the force exerted by the tie spring to the walkingbeams and the bearing means therebetween; to locate symmetrically on thefirst and second walking beams the mutually engageable abutment means totransmit substantially equal and simultaneous acceleration forces to thedistal ends of the second walking beam; to enclose each pair of parallelconnected separable main and auxiliary contacts in an insulating housingfilled with an arc extinguishing gas, with a conducting mechanismhousing supporting one end of each insulating housing and connecting thepairs of separable main and auxiliary contacts in series circuitrelation; and to connect the series connected circuit interrupters inseries with a disconnecting switch and to operate the circuitinterrupters and the disconnecting switch in predetermined sequence toopen and close a high voltage circuit.

In the drawings: FIG. 1 is a view, in side elevation, of a high voltageswitch construction embodying this invention. FIG. 2 is a top plan viewof the switch construction shown in FIG. 1. FIGS. 3A-B, taken togetherin endto-end relation, show a vertical sectional view of one of thecircuit interrupters provided with series connected main and auxiliarypairs of contacts in parallel circuit relation. FIG. 4 is a perspectiveview and at an enlarged scale of the mechanism housing shown in FIGS. 1and 2, including portions of the circuit interrupters mounted thereonand a portion of the supporting rotatable insulator. FIG. 5 is a view,partly in side elevation and partly in section, of the first and secondwalking beams that form a part of the operating mechanism. FIG. 6 is atop plan view of the walking beams shown in FIG. 5, certain parts beingbroken away in order to show details of construction. FIG. 7 is aperspective view of the adjustment plate, latch for the second walkingbeam and certain immediately associated parts. FIG. 8 is a perspectiveview of the latch associated with the first walking beam. FIG. 9 is aperspective view of the mechanism cam and parts immediately associatedtherewith. FIG. 10 is a top plan view of the latch for the first walkingbeam and shows a portion of this walking beam. FIG. 11 is a top planview of the latch for the second walking beam and shows a portion of thespring retainer. FIG. 12 is a top plan view of a portion of themechanism cam and illustrates how the over travel cam functions. FIG. 13is a view, in side elevation, of the mechanism housing, one of the sidewalls being broken away and parts being shown in section to illustratemore clearly the details of construction. FIG. 14 is a top plan view ofthe mechanism housing shown in FIG. 13, certain parts being broken awayand others being shown in section. FIG. 15 is an end view looking fromleft to right of FIGS. 13 and 14, a portion of the mechanism housingbeing broken away to show certain of the internal details ofconstruction.

In FIGS. 1 and 2 the reference character 10 designates, generally, aswitch construction embodying this invention. It is intended foroperation on a 500 kv. 60 cycle alternating current system. However, itcan be employed on systems operating at different voltages with suitablemodifications. The switch construction 10 employs a horizontallyextending switch base 11 and carries at its left end a stationaryinsulator stack 12. Also extending upwardly from the switch base 11 arefirst, second and third rotatable insulator stacks 13, 14 and 15. Themechanism for rotating the second and third insulator stacks 14 and 15is described in detail in the above Bernatt patent. This operatingmechanism includes a shaft 16 that is rotatable about a horizontal axisand from which arms 17 and 18 extend. These arms are connected by links19 and 20 to arms 21 and 22 that are suitably connected to the secondand third rotatable insulator stacks 14 and 15 for rotating them onrotation of the shaft 16. Another arm 23 extends from the base of therotatable insulator stack 14 and is connected by a link 24 to an arm 25that extends radially from the base of the first rotatable insulatorstack 13. The arrangement preferably is such that, on rotation of theshaft 16 about its horizontal axis through 180 the second and thirdinsulator stacks 14 and 15 are each rotated in opposite directionsthrough 95 while the first insulator stack 13 is being rotated through102. The first, second and third rotatable insulator stacks 13, 14 and15 are arranged to rotate about their vertical axes. It will beunderstood that these figures for the extents of rotation of the variousmembers are stated for illustrative purposes and that other degrees ofrotation can be employed.

A disconnecting switch, shown generally at 27, is mounted on the secondand third rotatable insulator stacks 14 and 15. The disconnecting switch27 includes switch blades 28 and 29 that are secured to the upper endsof the second and third insulator stacks 14 and 15 for rotation in ahorizontal plane. Contacts 30 and 31 are carried by the distal ends ofthe switch blades 28 and 29 for contact engagement in the closedposition of the disconnecting switch 27. They are arranged to beseparated when the disconnecting switch 27 is operated to the openposition shown by broken lines in FIG. 2.

In order to etfect circuit interruption without external arcing, circuitinterrupters, shown generally at 32 and 33, are employed. The circuitinterrupters 32 and 33 are of identical construction and may be formedas illustrated in FIGS. 3A-B. For the details of construction of thecircuit interrupter 32 or 33 reference can be had to the aboveidentified Mikos et al. patent. One end of the circuit interrupter 32 iscarried by the stationary insulator stack 12 while the other end ismounted on a, mechanism housing 34 which is carried by the firstrotatable insulator stack 13. The other circuit interrupter 33 ismounted at one end on the mechanism housing 34 that preferably is formedof an aluminum alloy, while its other end is mounted on the secondrotatable insulator stack 14. End terminal pads 35 and 36 are providedon the stationary insulator stack 12 and on the third rotatableinsulator stack 15 to permit circuit connection to the switchconstruction 10. It will be understood that the circuit from the endterminal pad 35 extends through the circuit interrupter 32, mechanismhousing 34, circuit interrupter 33, blades 28 and 29 of thedisconnecting switch 27 to the end terminal pad 36. Since the switchconstruction is intended to operate at a relatively high voltage,voltage grading electrodes 37 and 38 are provided at the upper ends ofthe insulator stacks 12 and 13 and a voltage grading electrode 39 isprovided above the distal end of the third insulator stack 15. Theinsulator stacks 14 and 15 are provided with grading rings 40 and 41 attheir upper ends.

As pointed out, the switch blades 28 and 29 are arranged to rotate in ahorizontal plane between the switch closed and the switch openpositions. The circuit interrupters 32 and 33 are located in this samehorizontal plane. Viewed from above, the circuit interrupters 32 and 33are located on opposite sides of the vertical plane that extends throughthe switch blades 27 and 28 when they are in switch closed positionshown in FIG. 2. This arrangement permits the use of different lengthsof circuit interrupter units 32 and 33 without requiring different endmounting fittings. It is necessary to change only the spacing betweenthe insulator stacks 12, 13 and 14.

FIGS. 3A-B show certain of the internal details of construction of thecircuit interrupter 32. It will be under stood that the circuitinterrupter 33 is identical in construction. The circuit interrupter 32includes a cylindrical insulating housing 42 of porcelain which isprovided with end terminals 43 and 44 hermetically sealed thereto. Theend terminal 43 is connected to the end terminal pad 35 while the endterminal 44 is mounted on the mechanism housing 34 in a suitable manner.The insulating housing 42 is preferably filled with an arc extinguishinggas such as SP Within the gas filled insulating housing 42 there arelocated two pairs of translatory separable main contacts 45 and 46 thatare connected in series circuit relation. Each pair of main contacts 45and 46 includes a translatory main contact 47 and a relativelystationary main contact 43. It will be understood that the translatorymain contacts 47 are interconnected for conjoint horizontal movementwhich is effected by a translatory main contact operating member 49which is connected directly to the main contact 47 of the pair of maincontacts 45 and extends externally of the sealed insulating housing 42into the mechanism housing 34 for horizontal translatory movement in amanner to be described.

Connected in parallel circuit relation with the pairs of main contacts45 and 46 are pairs of translatory separable auxiliary contacts 53 and54 which are connected in series circuit relation. Each of the pairs ofauxiliary contacts 53 and 54 includes a translatory auxiliary contact 55and a relatively stationary auxiliary contact 56. Pump means, showngenerally at 57 and 58, are associated with the pairs of auxiliarycontacts 53 and 54, respectively, for the purpose of forcing the arcextinguishing gas into the space between the contacts 55 and 56 of eachof the pairs of auxiliary contacts 53 and 54 when they are opened tointerrupt the circuit. As described in the Mikos et a1. patent,provision is made for effecting simultaneous translatory movement of theauxiliary contacts 55 of each of the pairs of auxiliary contacts 53 and54, together with the simultaneous operation of the pump means 57 and58. Such movement is effected by the translatory auxiliary contactoperating member 59 which is connected directly to the auxiliary contact55 of the pair of auxiliary contacts 53 and which extends externally ofthe gas filled insulating housing 42 into the mechanism housing 34 foroperation by means to be described.

It will be observed that the main contacts 47 of each of the pairs ofmain contacts 45 and 46 have translatory movement in a horizontal planewhich is below the horizontal plane in which the auxiliary contacts 55of the pairs of auxiliary contacts 53 and 54 move.

While two pairs of translatory separable main contacts 45 and 46 havebeen illustrated along with parallel connected pairs of translatoryseparable auxiliary contacts 53 and 54,.it will be understood that agreater or lesser number of pairs of contacts can be employed. Forexample, only a single pair of main contacts 45 can be employed inparallel circuit relation with a single pair of auxiliary contacts 53.Likewise, three or four pairs of separable contacts can be employed inseries and parallel relation. The number of pairs of contacts employedin series is determined, in part, by the voltage of the circuit in whichthe switch construction 10 is connected and the circuit characteristics.

In FIG. 4 the translatory main contact operating members 49 of thecircuit interrupters 32 and 33 are shown as being connected by links 62and 63 to bifurcated distal ends 64 and 65 of a first walking beam,shown generally at 66, and formed of aluminum alloy casting. The firstwalking beam 66 is mounted for rotation on a shaft 67 which extendsupwardly into the mechanism housing 34. At its lower end the shaft 67 issecured by a key 68, FIG. 13, to rotate with a mechanism support 69which may be a ductile iron casting. The mechanism support 69, FIG. 4,is secured by bolts 70 to a flange 71 which, in turn, is secured bybolts 72 to a metallic fitting 73 that is mounted on and rotates withthe upper end of the insulator stack 13. The shaft 67 extends upwardlyfrom the mechanism support 69 through a flange bearing 74, FIG. 13, in ahub 75 that is integral with the mechanism housing 34. The shaft 67 isjournaled at its upper end inside the mechanism housing 34 in a mannerto be described.

In FIG. 4 the projecting ends of the auxiliary contact operating members59 from the circuit interrupters 32 and 33 are connected by links 76 and7'7 to bifurcated distal ends 73 and 79 of a second walking beam, showngenerally at 80, and formed preferably of aluminum alloy casting. Thesecond Walking beam 80 is rotatably mounted about the shaft 67 on thefirst walking beam 66.

While the walking beams 66 and 80 are shown as straight levers pivotedmidway their ends, they can be in the form of bell cranks if desired.

It will be observed that the main contact operating members 49 for thecircuit interrupters 32 and 33 are located in a common horizontal planewhich also includes the first walking beam 66. In like manner theauxiliary contact operating members 59 for the circuit interrupters 32and 33 are located in a horizontal plane that contains the secondwalking beam 80, this plane being located above the plane of the firstwalking beam 66 and parts connected thereto. These planes are slightlyabove and below the horizontal plane in which the switch blades 28 and29 of the disconnecting switch 27 are located.

FIGS. 5 and 6 show certain details of construction of the first andsecond walking beams 66 and 80. The first walking beam 66 is providedwith a central hub 31 having flange bearings 82 at its upper and lowerends for rotatable mounting on the shaft 67. The second walking beam 80has a depending central hub 33 with flange bearings 84 at its upper andlower ends for mounting on a bearing sleeve 35 carried by the centralhub 81. The walking beams 66 and 30 are interconnected, in part, by aprestressed tie torsion spring 86 which extends around the central hub83 and is suitably secured at its ends to the upper side of the walkingbeam 66 and the under side of the walking beam 30. Since the walkingbeam 80 is journaled on the central hub 81 of the first walking beam 66,the force exerted by the tie torsion spring 83 is confined to thesewalking beams and is not transmitted to the shaft 67.

The walking beams 66 and 80 are also arranged to be interconnected byabutment means 89 on the first walking beam 66, the abutment means 89being in the form of a pair of diametrically opposite sectors as seen inFIG. 6. The abutment means 89 have faces 90 and 91 that look in oppositedirections for engagement respectively with faces 92 and 93 ondiametrically opposite abutment means 94 carried by the second walkingbeam 80. FIG. 4 shows more clearly the arrangement of one of theabutment means 39 on the first walking beam 66 with respect to theabutment means 94 on the second walking beam 80. The arrangement is suchthat, on rotation of the first walking beam 66 in a circuit openingdirection, the abutment means 89 engages the faces 92 of the abutmentmeans 94. For the circuit closing direction on reverse rotation of thefirst walking beam 66, the abutment means 89 thereon are arranged toengage the other faces on the abutment means 94 for closing theauxiliary contacts 53 and 54 of the circuit interrupters 32 and 33.Since the faces 92 on the abutment means 94 are impacted withconsiderable force, bumper pads 95 are provided on the respective faces90 of the abutment means 89.

The central hub 81 of the first walking beam 66 is provided with avertically extending keyway 93, FIG. 6, for receiving a key 99, FIG. 13,for non rotatably securing thereon a hub 100 of a spring retainer 101 ofaluminum alloy casting. The spring retainer 101 is arranged to receivethe lower ends of nested torsion springs 102 and 103 which togethercomprise spring means acting to bias the separable contacts to the openposition in the circuit interrupters 32 and 33. The lower ends of thetorsion springs 102 and 103 are secured to the spring retainer 101 whiletheir upper ends are trapped by a spring adjusting plate 104 which has atoothed periphery 105, FIG. 7, that is arranged to be clamped in aposition to hold the springs 102 and 103 under predetermined tension bytoothed clamped plates 106. The clamp plates 106 are secured in positionby bolts 107 that extend into the mechanism housing 34. The upper end ofthe shaft 67 is journaled in a flanged bearing 103 that is centrallylocated on the spring adjusting plate 104. In order to make certain thatthe shaft 67 is at the same potential as the adjacent parts of themechanism housing 34, a shunt strap 109 is secured 'by bolts 110 to thespring adjusting plate 104 and carries a contact 111 for engaging theupper end of the shaft 67 A collar 112 is secured by a set screw to theshaft 67 below the flanged bearing 103. Flexible shunts 114 areconnected to the mechanism housing 34 and to the links 76 and 77 inorder to provide good connections between the conducting mechanismhousing 34 and the auxiliary contact operating members 59 to which thetran-slatory auxiliary contacts 55 are connected. The mechanism housing34 is provided with a removable cover 115 which is secured in place bybolts 116. This arrangement, together with the location of the springs102 and 103 on the spring retainer 101 in the upper part of themechanism housing 34, facilitates assembly of the operating mechanismand the tensioning of the springs 102 and 103.

It will be understood that the first walking beam 66 and thereby thesecond walking beam 80 is driven by the spring means comprising thetorsion springs 102 and 103 first to open the pairs of translatoryseparable main contacts 45 and 46 in each of the circuit interrupters 32and 33 followed by opening of the pairs of translatory separableauxiliary contacts 53 and 54 in these circuit interrupters. It isnecessary to hold the walking beams 66 and 80 against the biasing actionof the torsion spring 102 and 103 until the circuit is to be opened. Forthis purpose means are provided for latching the walking beams 66 and 80against rotation. The latching means includes a latch plate 119, FIGS.5-6, that is secured by screws to a flange 121 that depends from thefirst walking beam 66. A latch, shown generally at 122 in FIGS. 8, 10and 14 and referred to in certain of the claims as a first latch, isemployed for restraining the first walking beam 66 against rotation. Thelatch 122 includes a bell crank 123 that is rotatably mounted on a pivotpin 124 which is carried by an arm 125 that extends from a side wall ofthe mechanism housing 34. One arm 126 of the bell crank 123 carries alatch roller 127 that is arranged to engage the latch plate 119 on thefirst walking beam 66 in an overcenter toggle locked position. A finger128 extending endwise from the arm 126 limits rotation of the bell crank123 in the counterclockwise direction as viewed in FIG. 14. A torsionspring 129 acts to bias the bell crank 123 to the latched position.

The latch 122 is arranged to be unlatched by rotation in a clockwisedirection, FIG. 10, through a trigger 130 comprising a bell crank thatis rotatably mounted on a pivot pin 131 which is carried by the bellcrank 123. One arm 132 of the trigger 130 is urged against an adjustingscrew 133 by a torsion spring 134, FIG. 8, while its other arm 135 isarranged to be engaged by one of teeth 136abcd carried by a mechanismcam 137 that is shown more clearly in FIGS. 9 and 13. The mechanism cam137 has a central hub 138 which is provided with a key way 139 forreceiving a key 140 to secure the mechanism cam 137 to the shaft 67 forrotation therewith. By thus placing the mechanism cam 137 close to theend of the shaft 67 where operating torque is applied from the rotatableinsulator stack 13 to the mechanism support 69, only a short length ofthe shaft 67 is subjected to the applied torque. This is of particularimpor- 7 tance with respect to the torque required to wind up thesprings 102 and 103.

Referring again to FIGS. 8, 10 and 14, the latch 122 also hasassociated'therewith a pryout roller 141 which is carried by an arm 142of the bell crank 123. The pryout roller 141 is arranged to engage apryout surface 143, FIGS. 10 and 14, on the first walking beam 66. Thepurpose of this arrangement is to provide for positively moving thefirst Walking beam 66 in a direction to open the main contacts 45 and 46of each of the circuit interrupters 32 and 33 in the event that thesprings 102 and 103 are unable to initiate this operation. Such forcedopening of these contacts might be required in the event that they haveremained in the closed position for an extremely long time or becamewelded in the closed position as the result of current flow. Thearrangement is such that the first walking beam 66 can be rotatedthrough an angle of 6 as a result of further rotation of the latch 122by the mechanism cam 137.

The reason for employing the several teeth 136a bcd on the mechanism cam137 is to provide for engaging the arm 135 of the trigger 130 at variouspositions of the mechanism cam 137 corresponding to various positions ofthe rotatable insulator stack 13 where it is desired to initiate anopening operation of the switch construction 10 prior to rotating theinsulator stack 13 to the fully closed position. An extension 144 fromthe bell crank 123 is arranged to engage the flange 145 on the mechanismhousing 34 for the purpose of limiting rotation of the latch 122 in aclockwise direction.

The continued rotation of the mechanism cam 137 in a counterclockwisedirection as viewed in FIG. 9 after the latch 122 has been tripped isemployed for winding up the springs 102 and 103 and generally reclosingthe main and auxiliary contacts in the circuit interrupters 32 and 33.For this purpose the mechanism cam 137 has an arm 148 through which abolt 149 extends. The head 150 of the bolt 149 is arranged to engage anarm 151 of an overtravel pawl 152 that is shown in FIGS. 5, 6, 9, 12 and13. The over-travel pawl 152 is in the form of a bell crank and isr-otatably mounted by pivot pin 153 on the underside of the firstwalking beam 66. The over-travel pawl 152 includes an arm 154 on which aroller 155 is mounted. The roller 155 is arranged to engage a surface156 of an over-travel cam 157 that is secured by screws 158 to the hub75 that is integral with the mechanism housing 34. As long as the roller155 continues to engage the surface 156 of the over-travel cam 157 asurged by engagement of the head 150 on the bolt 149 carried by themechanism cam 137 with the .arm 151, the first walking beam 66 continuesto be rotated and the main and auxiliary contacts in the circuitinterrupters 32 and 33 continue to be moved toward their closedposition. Since it is desirable that these contacts be moved fully totheir closed positions, provision is made to permit the mechanism cam137 to move to a position slightly beyond the position corresponding tothe closed position of these contacts in order to insure that they havebeen closed. For this purpose the over travel cam 157 has a surface 160that extends radially with respect to the axis of rotation of the firstwalking beam 66. When the roller 155 moves from the surface 156 to aposition along the surface 160, further rotation of the mechanism cam137 merely causes the over travel pawl 152 to rotate about the pivot pin153 and does not effect any further movement of the first walking beam66. A torsion spring 161, FIG. 5, acts to bias the over travel pawl 152to the operative position as shown in FIG. 9. It is against the biasingforce of this spring 161 that the over travel pawl 152 is rotated to thealternate position shown by broken lines in FIG. 12.

When the first walking beam 66 is rotated in the manner described towardthe closed position of the circuit interrupters 32 and 33, the abutmentmeans 89 engage the abutment means 94 on the second walking beam 80 andeffect rotation of the latter. The rotation of the first and secondwalking beams 66 and continues until the main and auxiliary contacts inthe circuit interrupters 32 and 33 are fully closed and the latch 122has engaged the latch plate 119 to prevent reverse rotation of the firstwalking beam 66 and thereby of the second walking beam 80 under thebiasing action of the springs 102 and 103. It is desirable that movementof the second walking beam 80 be prevented momentarily after the latch122 is tripped and the first walking beam 66 rotates to open the maincontacts of the circuit interrupters 32 and 33. For this purpose thereis provided a latch plate 164, FIGS. 5-6, on the second walking beam 80.The latch plate 164 is secured by screws 165 to an upstanding flange 166on the second walking beam 80. The latch plate 164 is arranged to beengaged by a latch, shown generally at 167, in FIGS. 11 and 14 and isreferred to in certain of the claims as a second latch. The latch 167includes a latch arm 168 that is rotatably mounted by a pivot pin 169 onan arm 170 that extends inwardly from a side wall of the mechanismhousing 34. The latch arm 168 carries a latch roller 171 that isarranged to have over center toggle locked engagement with the latchplate 164 in fully latched position. A torsion spring 172 acts to biasthe latch arm 178 in a counterclockwise direction and into latchingengagement with the latch plate 164. In order to release the latch 167,the latch arm 168 is provided with an integral flange 173 having aninclined cam surface 174 which is arranged to be engaged by ,a roller175. The roller 175 is carried by a roller support bracket 176 that issecured by bolts 177 to an upstanding flange 178 on the spring retainer101. It will be recalled that the spring retainer 101 is keyed to thecentral hub 01 of the first walking beam 66. Accordingly, the roller 175is moved together with the first walking beam 66 and the tie torsionspring 86 is further stressed. At .a predetermined point in the movementof the first walking beam 66 toward the circuit opening position, theroller 175 is caused to engage the cam surface 174. As a result thelatch 167 is tripped by rotation of the latch arm 168 in a clockwisedirection to move the roller 171 out of latching engagement with thelatch plate 164. Then the second walking beam 80 is freed to rotatefirst under the influence of the tie spring 86 followed by engagement ofthe abutment means 94 on the second walking beam 80 by the abutmentmeans 8 9 on the first walking beam 66. Some of the kinetic energyincident to the rotation of the first walking beam 66 is transmitted bythis impact to the second walking beam 00. Momentarily the springs 102and 103 drive through the first walking beam 66 to the second walkingbeam 80 to open the auxiliary contacts in the circuit interrupters 32and 33. The walking beam 80 accelerates to catch up to walking beam 66so that they reach full open position at about the same instant. Anextension 179 from the latch arm 168 acts as a stop for rotation in aclockwise direction on engagement with a flange 180 extending inwardlyfrom a side wall of the mechanism housing 34.

At the ends of the opening movements of the main and auxiliary contactsin the circuit interrupters 32 and 33 it is desirable that furthermovement thereof in the opening directions be stopped with a minimum ofshock. For this purpose, as shown in FIGS. 5 and 14, the bifurcateddistal ends 64 and 65 of the first walking beam 66 are provided withimpact surfaces 184 and 185 that are arranged to engage resilient bumperassemblies shown generally at 186 and 187, FIG. 14. Likewise, the distalends 78 and 79 of the second walking beam 80 are provided with impactsurfaces 188 and 189 for engaging these same bumper assemblies 186 and187.

It will be understood that the separable main and. auxiliary contacts inthe circuit interrupters 32 and 33 and the positions of the first andsecond walking beams 66 and 80 in the mechanism housing 34 are notreadily visible. However, it is desirable that some-means be providedfor indicating externally and positively whether these contacts are inthe open or the closed position. This can be accomplished by displayingexternally an indication of the position of the first walking beam 66.For this purpose, as shown in FIGS. 13, 14 and 15, a finger 194 ismounted by screws 195 on a fitting 196 into which the threaded end ofthe main contact operating member 49 of the circuit interrupter 32 isscrewed. Pins 197 extend from this fitting 196 and through theassociated links 62. The finger 194 extends downwardly to engage an arm198 that forms a part of a bell crank 199 which is rotatably mounted ona pivot pin 200 that is carried by bottom cover 34 mounted on themechanism housing 34. A torsion spring 201 acts to bias the bell crank199 in order to maintain the arm 198 in engagement with the distal endof the finger 194. The bell crank 199 also includes an arm 292 which hasa depending bifurcated end 203 between the furcations of which a pin 204extends. The pin 264 is carried by an indicator drum 205 at a positionoffset from its axis of rotation on pivots 206 suitably journaled on thebottom cover 34'. The indicator drum 205 carries suitable indicia, suchas colored reflecting tape or the like, which can be viewed through awindow 207 on the underside of the bottom cover 34', the color thatappears in the window 207 corresponding to the position of the firstwalking beam 66 and thereby the positions of the separable contacts inthe circuit interrupters 32 and 33.

In describing the operation of the switch construction 10 it will beassumed that it is in the closed position indicated in FIGS. 1 and 2 ofthe drawings and that the separable main and auxiliary contacts in thecircuit interrupters 32 and 33 are in the closed positions as shown inFIGS. 3A-B. In this closed poistion the pair of translatory spearablemain contacts 45 in each of the circuit interrupters 32 and 33 areconnected in series circuit relation through the mechanism housing 34.Likewise, the pairs of translatory separable auxiliary contacts 53 inthe circuit interrupters 32 and 33 are connected in series circuitinterrupters 32 and 33 are connected in series circuit relation throughthe mechanism housing 34 and also they are connected in parallel circuitrelation with the respective pairs of main contacts 45. Depending uponwhether or not they are provided, additional pairs of main and auxiliarycontacts are connected in series and parallel relation in the samerespect. The various parts of the operating mechanism within themechanism housing 34 occupy the positions shown by full lines in FIGS.515, it being understood that the roller 171 on the latch arm 168 of thelatch 167 is spaced slightly from the latch plate 164.

In opening the switch construction the arrangement is such that thecircuit is interrupted by the circuit interrupters 32 before thecontacts 30 and 31 at the distal ends of the switch blades 28 and 29 areseparated. Suitable means are provided for rotating the shaft 16, FIGS.1 and 2, to rotate insulator stacks 14 and 15 and initiate rotation ofthe switch blades 28 and 29 to their full open positions as shown bybroken lines. Through the link 24 the insulator stack 13 is rotated torotate the shaft 67 and therewith the mechanism cam 137. The first tooth136a, FIG. 10, on the mechanism cam 137 engages the arm 135 of thetrigger 130 and bodily rotates the latch 122 to move the latch roller127 to the position as shown by broken lines and out of engagement withthe latch plate 119. In the event that the first walking beam 66 doesnot immediately rotate under the influence of the springs 102 and 103,the continued rotation of the mechanism cam 137 swings the pryout roller141 into engagement with the pryout surface 143 on the first walkingbeam 66 and it is forced to begin rotation in a clockwise direction. Theforce acting to rotate the first walking beam 66 from the springs 102and 103 is transmitted directly thereto the spring retainer 101 which iskeyed by the key 99 to the hub 81 of the first walking beam 66.Conjointly with rotation of the first walking beam 66, the main contactoperating members 49 are pulled into the mechanism housing 34 and themain contacts 47 are caused to separate from the stationary contacts 48of the pairs of main contacts 45 and 46 in each of the circuitinterrupters 32 and 33. The current flow then is transferred entirely tothe pairs of auxiliary contacts 53 and 54 in each of the circuitinterrupters 32 and 33.

Shortly after the first walking beam 66 starts to rotate in a circuitopening direction, the faces 91 on the abutment means 89 that had beenin engagement with the faces 93 on the abutment means 94 of the secondwalking beam .move out of engagement therewith and permit the secondwalking beam 81) to rotate slightly until the latch plate 164 thereon isengaged by the latch roller 171 of the latch 167, FIG. 11. The secondwalking beam 81) then is held momentarily against further rotation.

As rotation of the first walking beam 66 continues, the bumper pads 95on the faces 90 of the abutment means 89 engage the faces 92 ontheabutment means 94. Concurrently therewith the roller 175, FIG. 11,engages the inclined cam surface 174 on the latch 167 to move the latchroller 171 out of latching engagement with the latch plate 164. Theimpact delivered by the first walking beam 66 to the second walking beam80 together with the biasing action of the tie spring 86 acts toaccelerate the second walking beam 80. Since the second walking beam 80is engaged simultaneously at diametrically opposite positions, itsdistal ends '78 and 79 are subjected to substantially equal andsimultaneous acceleration forces which forces are employed for effectingtranslatory movement of the auxiliary contact operating members 59 andthereby of the pairs of auxiliary contacts 53 and 54 in each of thecircuit interrupters 32 and 33 together with their respective pump means57 and 58. As shown in FIG. 11 the latch 167 is rotated to the positionshown by broken lines for unlatching the second walking beam 80.

Once the latch 122 has been tripped and the first walking beam 66 startsto rotate, the circuit is interrupted by the circuit interrupters 32 and33 independently of the speed of rotation of the insulator stack 13. Atthe end of its travel the distal ends 64 and 65 engage the bumperassemblies 136 and 187. Likewise, at the end of the movement of thesecond walking beam 80, its distal ends 78 and 79 also engage the bumperassemblies 186 and 187. After the circuit has been opened by the circuitinterrupters 32 and 33, the contacts 30 and 31 at the ditsal ends of theswitch blades 28 and 29 are separated and the switch blades 28 and 29are swung to the position shown by broken lines in FIG. 2. Here an airgap is provided in series with the circuit interrupters 32 and 33.

As the insulator stack 13 continues to be rotated on the continuedrotation of the switch blades 28 and 29 toward their full openpositions, the mechanism cam 137 is rotated to carry with it the bolt149 to the position shown by broken lines in FIG. 12. During the openingoperation of the circuit interrupters 32 and 33 the first walking beam66 comes to rest in the position shown in FIG. 12 by full lines againstthe bumper assemblies 186 and 187. As shown by the broken line positionof the bolt 149, the head 150 thereof engages the arm 151 of the overtravel pawl 152 and the continued rotation of the mechanism cam 137starts the rotation-of the first walking beam 66 toward the positionshown by broken lines in FIG. 12. Since the roller 155 on the overtravel pawl 152 engages the surface 156 on the over travel cam 157, norotation of the over travel pawl 152 takes place relative to the firstwalking beam 66 and the latter is rotated conjointly with the rotationof the mechanism cam 137 sequentially to move the main contacts 45 and46 and the auxiliary contacts 53 and 54 back to the circuit closedposition where they are held by the latch 122, FIG. 10, reacting againstthe latch plate 119 on the first walking beam 66. During this operationthe springs 102 and 103 are wound up. As described, the continuedrotation of the mechanism cam 148 causes the roller 155 to move from thesurface 156 to the surface 160 on the over travel cam 157. This permitsthe mechanism cam 137 to rotate slightly past the position where thelatch 122 holds the first walking beam 66 and the main contacts 45 and46 in each of the circuit interrupters 32 and 33 in the closed position.The rotation 11 of the first walking beam 66 in a closing directionmoves the faces 91 on the abutment means 89 into engagement with thefaces 93 on the abutment means 94 of the second walking beam 80.Accordingly, it is rotated together with movement of the auxiliarycontacts 53 and 54 in each of the circuit interrupters 32 and 33 to theclosed position.

At the end of the opening movement of the shaft 16, FIGS. 1 and 2, thedisconnecting switch 27 is in the open position and the circuitinterrupters 32 and 33 have been reclosed. The switch construction thenis in readiness for reclosure of the disconnecting switch 27 to befollowed by the next circuit opening operation.

As the first walking beam 66 is rotated from one position to the other,the indicator drum 205 is rotated from one position to another in orderto indicate the corresponding positions of the contacts in the circuitinterrupters 32 and 33.

What is claimed as new is:

1. In a high voltage circuit interrupter:

two pairs of translatory separable contacts in series circuit relation,

a translatory operating member for each pair of separable contacts,

a walking beam rotatably mounted between its distal ends, link meansinterconnecting said operating members and said distal ends of saidwalking beam,

spring means biasing said Walking beam to rotate it to open said pairsof separable contacts substantially simultaneously, and

latch means cooperating with said walking beam to prevent rotationthereof by said spring means to open said pairs of separable contacts.

2. The high voltage circuit interrupter of claim 1, wherein pryout meanson the latch means cooperate with the walking beam to initiate rotationthereof if the spring means is unable to do so.

3. The high voltage circuit interrupter of claim 1, wherein:

a mechanism cam rotatable about the axis of rotation of the walking beamcooperates with the latch means to unlatch. it to permit the springmeans to rotate said walking beam and open the pairs of separablecontacts, and

abutment means on said mechanism cam operatively engages said walkingbeam to rotate it in a direction to wind up said spring means, closesaid pairs of separable contacts and to rotate said walking beam to aposition to be held against reverse movement by said latch means.

4. The high voltage circuit interrupter of claim 3, wherein themechanism cam is operatively engageable with the latch at a plurality ofangular positions whereby said latch can be tripped at differentoperating positions of said mechanism cam.

5. The high voltage circuit interrupter of claim 3, wherein:

an over travel pawl is rotatably mounted on the walking beam and has onearm for engagement by the abutment means and another arm acting as a camfollower, and

an over travel cam cooperates with said cam follower to prevent rotationof said over travel pawl relative to said walking beam during a portionof its rotation by said abutment means on the mechanism cam until saidwalking beam is rotated to a predetermined position whereupon said overtravel pawl is permitted by said over travel cam to rotate relative tosaid walking beam and continued rotation of said mechanism cam isineffective to rotate said walking beam.

6. In a high voltage circuit interrupter:

two pairs of translatory separable main contacts connected in seriescircuit relation,

two pairs of translatory separable auxiliary contacts connected inseries circuit relation and in parallel connected circuit relationrespectively with said pairs of main contacts,

a translatory operating member for each pair of separable contacts,first and second walking beams rotatably mounted about a common axisbetween their distal ends,

link means interconnecting the operating members for each pair ofseparable main contacts and the distal ends of said first walking beam,

link means interconnecting the operating members for each pair ofseparable auxiliary contacts and the'distal ends of said second walkingbeam,

means operatively interconnecting said walking beams,

and

means for rotating said first walking beam to open said pairs ofseparable main contacts and thereafter rotating said second walking beamto open said pairs of separable auxiliary contact-s substantiallysimultaneously.

7. The high voltage circuit interrupter of claim 6, wherein the pairs ofseparable main contacts, operating members therefor, and the firstwalking beam are located in a plane and the pairs of separable auxiliarycontacts, operating members therefor, and the second walking beam arelocated in a plane parallel to the first mentioned plane.

8. The high voltage circuit interrupter of claim 6, wherein the meansoperatively interconnecting the first and second walking beam includes:

a tie spring acting to bias said second walking beam for rotationrelative to said first walking beam, and abutment means on said firstwalking beam for engaging abutment means on said second walking beam.

9. The high voltage circuit interrupter of claim 8, wherein:

the means for rotating the first walking beam and thereafter the secondwalking beam includes spring means to bias said first walking beam toopen the pairs of separable main contacts followed by opening of thepairs of auxiliary contacts,

a first latch cooperates with said first walking beam to preventmovement thereof to open said pairs of separable main contacts,

a second latch cooperates with said second walking beam to preventmovement thereof to open said pairs of separable auxiliary contacts, and

means carried by said first walking beam cooperates with said secondlatch to unlatch it to permit the tie spring and said spring means torotate said second walking beam and open the pairs of separableauxiliary contacts.

10. The high voltage circuit interrupter of claim 9,

wherein:

a mechanism cam rotatable about the axis of rotation of the walkingbeams cooperates with the first latch to unlatch it to permit the springmeans to rotate the first walking beam, and

abutment means on said mechanism cam operatively engages said firstwalking beam to rotate it and thereby the second walking beam in adirection to wind up the tie spring and said spring means, close thepairs of separable main and auxiliary contacts and to rotate saidwalking beams to positions where they are held against reverse rotationby said first latch.

11. In a high voltage circuit interrupter:

two pairs of translatory separable main contacts connected in seriescircuit relation,

two pairs of translatory separable auxiliary contacts connected inseries circuit relation and in parallel circuit relation respectivelywith said pairs of main contacts,

a translatory operating member for each pair of separable main andauxiliary contacts,

a rotatable shaft,

first and second walking beams rotatably mounted on said shaft midwaytheir distal ends,

link means interconnecting the operating members for each pair ofseparable main contacts and the distal ends of said first walking beam,

link means interconnecting the operating members for each pair ofseparable auxiliary contacts and the distal ends of said second walkingbeam,

means operatively interconnecting said walking beams,

spring means biasing said first walking beam for rotation to open saidpairs of separable main contacts followed by rotation of said secondwalking beam to open said pairs of separable auxiliary contacts,

a latch cooperating with said first walking beam to prevent rotationthereof by said spring means,

a mechanism cam rotatable with said shaft to unlatch said latch onrotation of said shaft to a predetermined position to permit said firstwalking beam to rotate and open said pairs of separable contacts.

12. The high voltage circuit interrupter of claim 11,

wherein:

bearings rotatably support the shaft at its ends,

drive means is connected to one end of said shaft for rotating it,

the means operatively interconnecting the walking beams includes:

a tie spring acting to bias the second walking beam for rotationrelative to said first walking beam, and

abutment means on said first walking beam for engaging abutment means onsaid second walking beam,

bearing means rotatably mounting said second walking beam on said firstwalking beam whereby the force exerted by said tie spring is confinedsubstantially entirely to said bearing means.

13. The high voltage circuit interrupter of claim 12, wherein theabutment means on the first and second walking beams are symmetricallylocated in pairs thereon to transmit substantially equal andsimultaneous acceleration forces to the distal ends of the secondwalking beam substantially without reaction against the bearing meansbetween said walking beams.

14. The high voltage circuit interrupter of claim 11, wherein:

bearings rotatably support the shaft at its ends,

drive means is connected to one end of said shaft for rotating it,

the spring means includes a torsion spring coiled around said shaft,

means anchor one end of said torsion spring adjacent the other end ofsaid shaft and the other end of said torsion spring to the first walkingbeam,

abutment means on the mechanism cam operatively en gages said firstwalking beam to rotate it and thereby the second walking beam in adirection to wind up said torsion spring, close the pairs of separablemain and auxiliary contacts and to rotate said walking beams topositions where they are held against reverse rotation by the latch, and

means secure said mechanism cam to said shaft adjacent said one endthereof whereby the torque for rotating said walking beams, closing saidpairs of contacts and winding up said torsion spring is transmittedthrough a relatively short portion of said shaft.

15. The high voltage circuit interrupter of claim 14,

wherein:

the means for anchoring one end of the torsion spring includes anadjustable anchor plate carrying the hearing for the other end of theshaft, and

clamp mean-s cooperate with said anchoring means for holding it in aposition where a predetermined tension is applied to said torsionspring.

16. The high voltage circuit interrupter of claim 11,

wherein:

an insulating housing individual to each pair of paral- 14 lel connectedmain and auxiliary contacts supports the same, a conducting mechanismhousing mechanically supports one end of each insulating housing andelectrically connects the pairs of separable main and auxillary contactsin series circuit relation, and bearings carried by said mechanismhousing rotatably support therein the shaft and the first and secondwalking beams mounted thereon. 1 17. The high voltage circuitinterrupter of claim 16,

wherein:

the insulating housings are sealed from the atmosphere and from themechanism housing,

an arc extinguishing gas fills each housing,

the translatory operating member for each pair of separable main andauxiliary contacts extends from the respective sealed housing into saidmechanism housing, and

pump means in each insulating housing operated by the operating memberfor the respective separable auxiliary contacts for causing a flow ofsaid are extinguishing gas into the space between said auxiliarycontacts on separation thereof.

18. The high voltage circuit interrupter of claim 11,

wherein:

disconnecting switch means are connected in series circuit relation withthe pairs of series and parallel connected separable main and auxiliarycontacts, and

means are provided for rotating the shaft to open said separable mainand auxiliary contacts and subsequently to open said disconnectingswitch means.

19. High voltage switch means comprising switch blade means movablebetween switch closed and switch open positions,

a pair of circuit interrupters connected in series circuit relation andin series circuit relation with said switch blade means,

said circuit interrupters being positioned in end to end relation withsaid switch blade means,

said circuit interrupters being positioned in end to end relation and onopposite sides of the plane of said switch blade means in switch closedposition,

operating means for said circuit interrupters at their juxtaposed ends,and

means operatively interconnecting said switch blade means and saidoperating means for opening and closing said switch blade means and saidcircuit interrupters in predetermined sequence.

20. The high voltage switch means of claim 19, wherein the switch blademeans includes a pair of center break switch blades rotatable in a planeat right angles to the plane on opposite sides of which the circuitinterrupters are positioned.

21. The high voltage switch construction of claim 20, wherein thecircuit interrupters are positioned in the plane in which the switchblades are movable.

22. The high voltage switch means of claim 19, wherein:

a conducting mechanism housing supports the circuit interrupters attheir juxtaposed ends, provides the series connection therebetween, andencloses the operating means therefor, and

each circuit interrupter includes an insulating housing sealed from theatmosphere and from said mechanism housing and filled with an arcextinguishing gas.

References Cited UNITED STATES PATENTS 4/1961 Friedrich 200-148 FOREIGNPATENTS 34,091 4/1951 Poland.

ROBERT K. SCHAEFER, Primary Examiner. 75 H. J. HOHAUSER, AssistantExaminer.

1. IN A HIGH VOLTAGE CIRCUIT INTERRUPTER: TWO PAIRS OF TRANSLATORYSEPARABLE CONTACTS CONNECTED IN SERIES CIRCUIT RELATION, A TRANSLATORYOPERATING MEMBER FOR EACH PAIR OF SEPARABLE CONTACTS, A WALKING BEAMROTATABLY MOUNTED BETWEEN ITS DISTAL ENDS, LINK MEANS INTERCONNECTINGSAID OPERATING MEMBERS AND SAID DISTAL ENDS OF SAID WALKING BEAM, SPRINGMEANS BIASING SAID WALKING BEAM TO ROTATE IT TO OPEN SAID PAIRS OFSEPARABLE CONTACTS SUBSTANTIALLY SIMULTANEOUSLY, AND LATCH MEANSCOOPERATING WITH SAID WALKING BEAM TO PREVENT ROTATION THEREOF BY SAIDSPRING MEANS TO OPEN SAID PAIRS OF SEPARABLE CONTACTS.